What is the point of bearings?

Imagine you want to sail a ship from Liverpool to new York. While sailing you will need to know precisely what direction you need to be travelling at every point(if you are out by one degree this could result in being kms out from your destination ). To do this we could use a compass but the directions on a campus will rarely be precise enough (North, East, South, West), so instead we use bearings which allow for as much precision as you would like.